A scanner system has recently prevailed in the graphic arts. Various kinds of light sources have been used in practice in recording apparatuses of the type which adopt a scanner system at the formation of images. In particular, a He--Ne laser has come into wide use because it is stable and can provide a high image quality. The exposure time in the scanning exposure is very short, and ranges from 10.sup.-3 to 10.sup.-7 second. Therefore, it is required that photosensitive materials for scanning exposure use have high sensitivity and provide high contrast images even upon such short exposure as described above.
Further, workers in the graphic arts are strongly desirous that operations be increased in speed and efficiency, that is, that the scanning operation be speeded up and the processing time of photosensitive materials be shortened. With respect to the developer and the fixer used in the processing operation, it is desirable that the amounts of developer and fixer to be used be reduced from the viewpoints of storage and recovery cost of the wastes or environmental pollution problems, so that expectations for reduction in the replenishment rates of the developer and the fixer are on the rise.
As a photosensitive material suitable for exposure with an He--Ne light source and for rapid processing, JP-A-3-59637 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") discloses a photosensitive material in which carbocyanine or rhodacyanine dyes are used as spectral sensitizers and the gelatin contents of the emulsion layers and protective layers are specified. In addition, the above reference discloses in its examples silver chlorobromide emulsions which contain iridium and rhodium and which are sensitized with gold and sulfur compounds. However, the photosensitive material cited above is low in sensitivity and is not wholly satisfactory with respect to the consistency in photographic properties achieved by continuous photographic processing performed under a reduced replenishment condition, though it is satisfactory from the viewpoints of gradation and color stain.